Wellhead assembly having a sinusoidal sealing profile and a method to assemble the same

Abstract

An outer tubular wellhead member having wickers formed in a bore of the outer tubular wellhead member that vary in axial position and methods to assemble a subsea wellhead including the same is disclosed. The plurality of circumferentially extending wickers are formed in sealing profiles of the wellhead member. Each wicker varies axially in position around the circumference of the bore so that when a seal member engages each wicker, the wicker deforms the surface of the annular seal to form circumferential sealing bands at each wicker from an upper end of the sealing profile to a lower end of the sealing profile, upper portions of each wicker deforming the surface of the annular seal before lower portions of the same wicker so that fluid between adjacent wickers flows from the higher axial location of the wicker to the lower axial location of the wicker to limit hydraulic lock.

What is claimed is: 
     
         1 . A wellhead assembly comprising:
 an outer tubular wellhead member with a bore having an axis and a sealing surface extending an axial distance along an inner diameter surface of the bore;   wickers in the sealing surface circumscribing the bore along an axially undulating path;   an inner tubular member in the outer tubular wellhead member; and   a seal element between the inner tubular wellhead member and the outer tubular wellhead member and urged against the wickers to form a sealing interface.   
     
     
         2 . The wellhead assembly of  claim 1 , wherein the axial position of each wicker varies sinusoidally. 
     
     
         3 . The wellhead assembly of  claim 2 , wherein each wicker of the plurality of wickers is substantially parallel to adjacent wickers. 
     
     
         4 . The wellhead assembly of  claim 1 , wherein the wickers are equidistantly spaced from each adjacent wicker. 
     
     
         5 . The wellhead assembly of  claim 1 , further comprising wickers in a sealing surface on an outer diameter surface of the inner tubular member, the wickers circumscribing the inner tubular member along an axially undulating path. 
     
     
         6 . The wellhead assembly of  claim 1 , further comprising partial wickers in the sealing surface, wherein each partial wicker extends along a portion of the circumference of the bore and follows an axially undulating path. 
     
     
         7 . The wellhead assembly of  claim 6 , wherein partial wickers are proximate axial ends of the sealing surface. 
     
     
         8 . The wellhead assembly of  claim 6 , wherein each of the partial wickers are substantially similar. 
     
     
         9 . The wellhead assembly of  claim 6 , wherein adjacent partial wickers are equidistantly spaced from each other. 
     
     
         10 . A wellhead assembly comprising:
 an outer tubular wellhead member with a bore having an axis and a sealing surface extending an axial distance along an inner diameter surface of the bore;   wickers in the sealing surface circumscribing the bore along an axially undulating path;   partial wickers in the sealing surface, wherein each partial wicker extends along a portion of the circumference of the bore and follows an axially undulating path;   an inner tubular member in the outer tubular wellhead member; and   a seal element between the inner tubular wellhead member and the outer tubular wellhead member and urged against the wickers to form a sealing interface.   
     
     
         11 . The wellhead assembly of  claim 10 , further comprising wickers in a sealing surface on an outer diameter surface of the inner tubular member, the wickers circumscribing the inner tubular member along an axially undulating path. 
     
     
         12 . The wellhead assembly of  claim 11 , further comprising partial wickers in the sealing surface on the outer diameter surface of the inner tubular member, wherein each partial wicker extends along a portion of the outer diameter surface and follows an axially undulating path 
     
     
         13 . The wellhead assembly of  claim 10 , wherein the axial position of each wicker varies sinusoidally. 
     
     
         14 . The wellhead assembly of  claim 10 , wherein each wicker of the plurality of wickers is substantially parallel to adjacent wickers. 
     
     
         15 . A method of forming a wellhead assembly comprising:
 (a) providing an outer tubular wellhead member having a bore, an axis, and an inner surface of the outer tubular wellhead member having wickers that circumscribe the bore and vary axially in position around the circumference of the bore;   (b) inserting an inner tubular wellhead member in the outer tubular wellhead member;   (c) inserting an annular seal in an annulus between the outer tubular wellhead member and the inner tubular wellhead member; and   (d) urging the seal against the wickers so that the wickers deform the seal and create a barrier in the annulus.   
     
     
         16 . The method of  claim 15 , wherein step (a) further comprises providing each wicker with a sinusoidally varying axial position. 
     
     
         17 . The method of  claim 15 , wherein step (a) further comprises providing wickers on an outer circumference of the inner tubular wellhead member. 
     
     
         18 . The method of  claim 15 , wherein step (a) further comprises providing partial wickers on the outer tubular wellhead member, wherein the partial wickers extend along a portion of the circumference of the bore.